Low density edible animal chews and methods of making same

ABSTRACT

Edible chews for pets have a low density (e.g. about 1.0 Kg/L or less) and a smooth exterior surface. One method by which the low density and the smooth exterior surface can be achieved uses a modified extrusion die to increase shear and restrict surface bubbles. Another method by which the low density and the smooth exterior surface can be achieved uses an extruder screw with a modified profile that holds a dough longer therein to create a whipping effect resulting in more bubble nucleation sites and hence a more uniform cellular matrix. The puffed (expanded) product was experimentally tested and provided better dental cleaning scores than a current unexpanded similarly formulated commercial dental product.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application No.62/083,567 filed Nov. 24, 2014, the disclosure of which is incorporatedherein by this reference.

BACKGROUND

The present disclosure relates generally to low density edible chewshaving a cellular matrix that provides sufficient bite depth tofacilitate mechanical teeth cleaning and further relates to methods ofmaking such chews. More specifically, the present disclosure is directedto edible chews having a low density and a smooth exterior surface thatcan be achieved by modifying an extrusion process.

Animal chew toys are designed to entertain the animal, combat animalboredom, prevent destructive animal chewing behavior, and provide anoutlet for an animal's innate chewing instinct. Generally, animal chewtoys are made from plastic or other material that cannot be eaten by theanimal. Animals typically tire of non-edible animal chew toys after ashort period of time and move on to other activities. Moreover,non-edible animal chew toys provide no nutritional value to the animaland are limited in providing a health benefit to the animal.

Edible chews have been developed, but they are based on expensiveingredients, mainly pre-gelatinized rice or corn, which have a negativeimpact on the manufacturing cost. Furthermore, known edible chews haverelatively poor dental efficacy (around 30-35% tartar build upreduction) for two potential reasons: their limited thickness (the teethdo not penetrate very deeply into the chew before breakage) and theirlimited duration.

A lower density of the chew could possibly require the animal teeth topenetrate deeply into the chew. However, to the best knowledge of thepresent inventors, there is no known solution to obtain highlyperforming and appealing low density chews, especially from formulaebased on pre-gelatinized starches. In this regard, the expansion ofpre-gelatinized starches is difficult to monitor, and the final productshape is difficult to control. For example, the final product has a veryrough surface and a burgeoning structure that is unsatisfactory. In thisregard, standard extrusion dies with a smooth surface, whatever theshape, lead to an unappealing product surface with numerous blisters(“toad skin”).

SUMMARY

The present disclosure provides edible chews having a low density (e.g.about 1.0 Kg/L or less) and a smooth exterior surface. As a non-limitingexample, the low density and the smooth exterior surface can be achievedby modifying an extrusion die to restrict surface bubbles. As anothernon-limiting example, the low density and the smooth exterior surfacecan be achieved by modifying the profile of an extruder screw to hold adough longer therein, to create a whipping effect resulting in morebubble nucleation sites and hence a more uniform cellular matrix. Inboth of these examples, the effect can be enhanced by adding abicarbonate such as sodium bicarbonate to produce smaller foam cells.

Accordingly, in a general embodiment, the present disclosure provides anedible pet chew comprising an expanded pre-gelatinized cereal flourmatrix and having a substantially smooth exterior surface and a densitynot greater than about 1.0 Kg/L.

In an embodiment, the chew has a form of single unitary piece.

In an embodiment, the chew does not contain a supercritical fluid.

In an embodiment, the chew has a caloric density of 1.5-2.7 Kcal/cm³.

In an embodiment, the density is at most about 0.9 Kg/L.

In an embodiment, the chew comprises a body having a substantiallycylindrical shape and comprises radial ridges extending from the bodyparallel to each other along at least a portion of the length of thebody.

In another embodiment, the present disclosure provides a method ofmaking an edible pet chew. The method comprises the steps of: preparinga dry mix comprising a pre-gelatinized cereal flour; metering the drymix into an extruder comprising an extrusion die; adding a hydrogenbond-forming component to the dry mix to form a dough; promotingnucleation of the dough by subjecting the dough to a combination ofshear and a temperature in a section of the extruder adjacent to theextrusion die to form a heated and sheared dough, the temperature in thesection adjacent to the extrusion die is higher than a temperature of atleast one previous section of the extruder; and directing the heated andsheared dough through an opening of the extrusion die comprisinggrooves, each of the grooves has an open end and a bottom surfaceopposite to the open end, and the width of the bottom surface is greaterthan the width of the open end.

In an embodiment, the grooves have a substantially triangularcross-section (dove-tail shape).

In an embodiment, the grooves have a width that continuously decreasesas the grooves extend toward the center of the opening.

In an embodiment, the grooves are evenly spaced along an inner peripheryof the opening of the extrusion die.

In an embodiment, the temperature in the section of the extruderadjacent to the extrusion die is at least 120° C.

In an embodiment, the hydrogen bond-forming component comprises apolyhydric solvent.

In another embodiment, the present disclosure provides a method ofmaking an edible pet chew. The method comprises the steps of: preparinga dry mix comprising a pre-gelatinized cereal flour and a bicarbonate;metering the dry mix into an extruder comprising an extrusion die;adding a hydrogen bond-forming component to the dry mix to form a dough;and promoting nucleation of the dough by subjecting the dough to acombination of shear and a temperature in a section of the extruderadjacent to the extrusion die to form a heated and sheared dough, thetemperature in the section adjacent to the extrusion die is higher thana temperature of at least one previous section of the extruder.

In an embodiment, the bicarbonate is sodium bicarbonate. The dry mix cancomprise 0.2 to 1.5 wt % of the sodium bicarbonate, for example 0.5 to1.5 wt % of the sodium bicarbonate.

In another embodiment, the present disclosure provides a method ofmaking an edible pet chew. The method comprises the steps of: preparinga dry mix comprising a pre-gelatinized (pregelled) cereal flour;metering the dry mix into an extruder comprising an extrusion die and abarrel comprising a vent and a vent-stuffer; adding a hydrogenbond-forming component to the dry mix to form a dough; using a reverseelement of the extruder to extend a time spent by the dough in thebarrel comprising the vent and the vent-stuffer; using mixing elementsin the barrel comprising the vent and the vent-stuffer to whip the doughand promote nucleation; and promoting further nucleation of the dough bysubjecting the dough to a combination of shear and a temperature in asection of the extruder adjacent to the extrusion die to form a heatedand sheared dough, the temperature in the section of the extruderadjacent to the extrusion die is higher than a temperature of at leastone previous section of the extruder. Extending the time spent by thedough in the first section can provide for a better whipping of thedough.

In an embodiment, the method comprises adding a bicarbonate to the drymix.

In an embodiment, the method comprises aerating the dough in the barrelcomprising the vent and the vent-stuffer.

In an embodiment, the vent and the vent-stuffer are configured toprovide ambient pressure.

In another embodiment, the present disclosure provides an edible petchew made by a process selected from the above methods.

In another embodiment, the present disclosure provides a pet treatcomprising: an edible pet chew comprising an expanded pre-gelatinizedcereal flour matrix and having a substantially smooth exterior surfaceand a density not greater than about 1.0 Kg/L; and at least one fillingcomprising radial sides surrounded by the edible pet chew.

In another embodiment, the present disclosure provides a method ofcleaning teeth of a pet, the method comprising administering to the petan edible pet chew comprising an expanded pre-gelatinized cereal flourmatrix and having a substantially smooth exterior surface and a densitynot greater than about 1.0 Kg/L.

An advantage of the present disclosure is to provide improved ediblechews for pets.

Another advantage of the present disclosure is to provide improvedmethods of making edible chews for pets.

Still another advantage of the present disclosure is to provide ediblepet chews that increase consumer appeal/credibility on a similar weightbasis compared to existing chews, due to product volume.

Yet another advantage of the present disclosure is to produce edible petchews at a reduced cost on a similar volume basis compared to existingchews.

Another advantage of the present disclosure is to provide edible petchews having reduced calories on a similar volume basis compared toexisting chews.

Still another advantage of the present disclosure is to provideincreased feeding opportunities due to improved edible chew properties(e.g. low caloric density and good resistance to shear), leading toincreased interactions between a dog and the owner of the dog.

Yet another advantage of the present disclosure is to provide edible petchews that have improved dental efficacy on a similar weight basiscompared to existing chews, due to an increased product thickness and apumice structure.

Still another advantage of the present disclosure is to provide ediblepet chews that have a low density and an aerated structure butnevertheless provide chewing properties on a similar weight basis ascompared to normal high density chews.

Yet another advantage of the present disclosure is to produce edible petchews that have a low density and thus provide an excellent volumeimpression, which may be used to reduce product weight and therefore rawmaterial cost.

Another advantage of the present disclosure is to provide edible petchews having a pumice structure that has a multi-blade effect thatachieves a better teeth-cleaning and therefore a better reduction oftartar build up compared to existing chews.

Still another advantage of the present disclosure is to provide lowdensity edible pet chews that have better a cosmetic impression thanblistered chews, by having larger smooth surfaces.

Yet another advantage of the present disclosure is to produce edible petchews that have a low density without using a supercritical fluid.

Another advantage of the present disclosure is to provide edible petchews that have an alveolar structure without compromising resistance toshear.

Still another advantage of the present disclosure is to provide lowdensity edible pet chews that have rubbery character.

Additional features and advantages are described herein, and will beapparent from the following Detailed Description and the Figures.

BRIEF DESCRIPTION OF THE FIGURES

FIGS. 1-5 are photographs of the edible pet chews made in theexperimental examples disclosed herein.

FIG. 6 is a front plan view of an embodiment of an extrusion dieprovided by the present disclosure.

FIGS. 7A and 7B are photographs of an edible pet chew made by theembodiment of an extrusion die shown in FIG. 6.

FIG. 8 is a photograph of an embodiment of an edible pet chew made usinga star-shaped insert according to the present disclosure.

FIG. 9A is a photograph of an embodiment of a device for making anedible pet chew comprising a filling according to the presentdisclosure.

FIG. 9B is front plan view of an embodiment of an extrusion die that canbe used in the device shown in FIG. 9A.

FIGS. 9C and 9D are photographs of an edible pet chew made by theembodiment of the device shown in FIG. 9A and the embodiment of anextrusion die shown in FIG. 9B.

FIGS. 10A and 10B are photographs of differently-shaped embodiments ofedible pet chews according to the present disclosure.

FIG. 11 is a close-up photograph of the cellular texture of anembodiment of an edible pet chew according to the present disclosure.

DETAILED DESCRIPTION

As used in this disclosure and the appended claims, the singular forms“a,” “an” and “the” include plural referents unless the context clearlydictates otherwise. Thus, for example, reference to “a meat” includestwo or more meats. The term “and/or” used in the context of “X and/or Y”should be interpreted as “X,” or “Y,” or “X and Y.”

As used herein, “about” and “substantially” are understood to refer tonumbers in a range of numerals, for example the range of −10% to +10% ofthe referenced number, preferably within −5% to +5% of the referencednumber, more preferably within −1% to +1% of the referenced number, mostpreferably within −0.1% to +0.1% of the referenced number. Furthermore,all numerical ranges herein should be understood to include allintegers, whole or fractions, within the range. Moreover, thesenumerical ranges should be construed as providing support for a claimdirected to any number or subset of numbers in that range. For example,a disclosure of from 1 to 10 should be construed as supporting a rangeof from 1 to 8, from 3 to 7, from 1 to 9, from 3.6 to 4.6, from 3.5 to9.9, and so forth.

All percentages expressed herein are by weight of the total weight ofthe composition unless expressed otherwise. When reference is made tothe pH, values correspond to pH measured at 25° C. with standardequipment. “Ambient pressure” is about 100 kPa.

The term “pet” means any animal which could benefit from or enjoy thecompositions provided by the present disclosure. For example, the petcan be an avian, bovine, canine, equine, feline, hircine, lupine,murine, ovine, or porcine animal, but the pet can be any suitableanimal. The term “companion animal” means a dog or a cat.

The terms “food,” “food product” and “food composition” mean a productor composition that is intended for ingestion by an animal, including ahuman, and provides at least one nutrient to the animal. The term “petfood” and “pet treat” mean any food composition intended to be consumedby a pet. The term “edible chew” means a comestible product thatrequires a longer chewing time before the product can be ingested,relative to a standard comestible product. Preferably the edible chewrequires at least one minute of chewing before the product can beingested, for example one to four minutes of chewing before the productcan be ingested. A “smooth surface” of the chew means a surface that issubstantially free from undulations, blisters and bumps.

“Dry food” is pet food having a water activity less than 0.75.“Semi-moist food” and “intermediate moisture food” is pet food having awater activity from 0.75 to 0.85. “Wet food” is pet food having a wateractivity more than 0.85.

The compositions disclosed herein may lack any element that is notspecifically disclosed herein. Thus, a disclosure of an embodiment usingthe term “comprising” includes a disclosure of embodiments “consistingessentially of” and “consisting of” the components identified.Similarly, the methods disclosed herein may lack any step that is notspecifically disclosed herein. Thus, a disclosure of an embodiment usingthe term “comprising” includes a disclosure of embodiments “consistingessentially of” and “consisting of” the steps identified.

In an aspect of the present disclosure, an edible pet chew having a lowdensity and a smooth exterior surface is provided. For example, theedible pet chew can have a density of 0.5 Kg/L to 1.0 Kg/L, for example0.5 Kg/L to about 0.9 Kg/L, such as about 0.9 Kg/L. In some embodiments,the edible pet chew has a density of about 0.5 Kg/L or less, such asabout 0.5 Kg/L. The edible pet chew preferably is a single unitary piecethat is substantially homogenous and has substantially the same texturethroughout. In an embodiment, the chew has a caloric density of 1.5Kcal/cm³ to 2.7 Kcal/cm³, for example about 2.1 Kcal/cm³. An edible chewtypically has a water activity of 0.65 to 0.75, but some embodiments ofthe edible pet chews disclosed herein have a slightly lower wateractivity, for example 0.6 to 0.7.

In an embodiment, the chew comprises a body having a substantiallycylindrical shape and comprises radial ridges extending from the bodyparallel to each other along at least a portion of the length of thebody, for example an entire length of the body (e.g. the embodimentshown in FIG. 8). However, the edible pet chew can have any shape (e.g.the embodiments shown in FIG. 10), and the edible pet chew is notlimited to a specific shape.

In another aspect of the present disclosure, a pet treat is providedcomprising the edible chew and one or more fillings therein. Forexample, the pet treat can be a co-extruded product comprising theedible chew and a soft filling surrounded at least on radial sides bythe edible chew (e.g. the filling can be exposed at the ends of thechew). The filling may contain additional teeth cleaning compounds, suchas Tetrasodium Pyrophosphate (TSPP) and/or breath-freshening compounds.

In yet another aspect of the present disclosure, a method of making anedible pet chew is provided. The method can comprise using a dry mix bymixing pre-gelatinized cereal flour to form a dry mix. Non-limitingexamples of suitable pre-gelatinized cereal flours includepre-gelatinized rice flour, pre-gelatinized wheat flour, pre-gelatinizedcorn flour, pre-gelatinized barley flour, pre-gelatinized sorghum flour,and pre-gelatinized millet flour, and combinations thereof. Optionallythe dry mix can include other components in addition to thepre-gelatinized cereal flour, such as one or more of a protein source,vitamin, a mineral, a preservative, an antioxidant, a colorant, apalatant, or a flavorant. Preferably the method of making an edible petchew does not involve using a supercritical fluid.

Non-limiting examples of suitable vitamins include vitamin A, any of theB vitamins, vitamin C, vitamin D, vitamin E, and vitamin K, includingvarious salts, esters, or other derivatives of the foregoing.Non-limiting examples of suitable minerals include calcium, phosphorous,potassium, sodium, iron, chloride, boron, copper, zinc, magnesium,manganese, iodine, selenium, and the like. In a particularly preferredembodiment, calcium hydrogen phosphate can be used as a calcium source.Non-limiting examples of suitable preservatives include potassiumsorbate, sorbic acid, sodium methyl para-hydroxybenzoate, calciumpropionate, propionic acid, and combinations thereof. The antioxidantcan provide an aesthetic effect and influence the odor of the edible petchew, particularly during extended shelf-life. Non-limiting examples ofsuitable antioxidants include butylated hydroxyanisole (BHA), butylatedhydroxytoluene (BHT), vitamin E (tocopherols), and combinations thereof.Non-limiting examples of suitable colorants include FD&C colors, such asblue no. 1, blue no. 2, green no. 3, red no. 3, red no. 40, yellow no.5, yellow no. 6, and the like; natural colors, such as roasted maltflour, caramel coloring, annatto, chlorophyllin, cochineal, betanin,turmeric, saffron, paprika, lycopene, elderberry juice, pandan,butterfly pea and the like; titanium dioxide; and any suitable foodcolorant known to the skilled artisan. Non-limiting examples of suitablepalatants flavorants include yeast, tallow, rendered animal meals (e.g.,poultry, beef, lamb, and pork), flavor extracts or blends (e.g., grilledbeef), animal digests, and the like.

The dry mix can contain emulsifiers and stabilizers such as soylecithin, mono- and di-glycerides, and the like. In an embodiment, thecomposition does not contain any lipids, and/or the emulsifier is theonly lipid in the composition. Meat flours can be added to the dry mixand would be a source of lipids. Chicken fat can be used to reducestickiness if needed, although higher temperature may be required toachieve the same expansion relative to a composition lacking chickenfat. In an embodiment, any protein from the pre-gelatinized cereal flouris the only protein in the composition. Some other protein sources mightbe used for substantiation of nutritional claims (e.g. meat meals,greaves meals, etc.), the addition level being appropriate not toprevent expansion.

A component capable of forming hydrogen bonds in the pre-gelatinizedcereal flour can be added to the dry mix to form dough that isdynamically cooked in an extruder. The component capable of forminghydrogen bonds is preferably added to the dry mix in the extruder. Thecomponent can comprise a polyhydric solvent which is preferablynon-aqueous and preferably ethylene glycol, propylene glycol, glycerolor a combination thereof. Water and/or an additional preservative mayalso be added to the dry mix. In an embodiment, the water content may befrom 7.5% to 11.9%, the glycerin content may be from 13.4% to 17.9%, andthe amount of the dry mix may be from 71.4% to 78.1% of the flour.

In the extruder, the dough constituents can mix with each other whileshear is imparted within the extruder barrel. Preferably the extruderhas a plurality of successive barrels, and the temperature increases inone or more of the barrels adjacent the die through which the cookeddough exits, relative to the prior barrels. For example, the barrel atthe exit end of the extruder can be heated to a temperature of about120° C., and one or more of the prior barrels can be heated to atemperature of about 80° C. The temperature increase at the exit end ofthe extruder can cause sudden and extensive formation of gas in thedough, resulting in expansion of the dough at both a microscopic andmacroscopic level as bubbling gas attempts to escape the material.

As a non-limiting example, the initial barrels (e.g. the 6 firstbarrels) are not heated, for example by having the temperature thereinset to around 25° C., although the temperature of these barrels is notnecessarily the set temperature because the cooling capacity is notalways sufficient. The temperature of the last barrels (e.g. the lastfour barrels) may be 80-120° C. for low product throughput (100-150kg/h) and may be lower for higher throughput (high shearing due to screwspeed). Moreover, the temperature of the last barrels can be lower ifthe last part of the screw profile therein is stronger. The averagepressure at the front plate can be about 75 bars at 115 kg/h on a onerope die; higher pressure (e.g. about 95 bars) can be reached at higherthroughput 400 kg/h on a four rope die. The average SME value can be400-450 KJ/kg on dry basis.

In a first embodiment, a low density (a density of about 0.7 Kg/L orless, such as about 0.7 Kg/L) and a smooth exterior surface of theedible pet chew can be achieved by at least one of the following: (i) aspecific design of the extrusion die or (ii) addition of a bicarbonatesuch as sodium bicarbonate to the dry mix. In this first embodiment, theextruded material is aerated; if the extruded material is not aerated,the density will be around 1.2-1.3 kg/L. Preferably, a venting barrel isnot used. In this first embodiment, the expansion can be primarily in aradial direction.

FIG. 6 generally illustrates an embodiment of an extrusion die 10 thatcan achieve a low density and a smooth exterior surface of the ediblepet chew. The extrusion die 10 can comprise dovetail grooves 11 throughwhich the material is extruded. For example, the extrusion die 10 cancomprise an opening 15, and the dovetail grooves 11 can be formed in theinner periphery 16 of the opening 15. Each of the dovetail grooves 11has an open end and a bottom surface that is opposite to the open end.

The dovetail grooves 11 each have an inner width and an outer width thatare perpendicular to the direction of extrusion (i.e. the longitudinalaxis of the extruder), the inner width is closer to the center of theopening 15, and each of the inner widths is shorter than thecorresponding outer width. The center of the opening 15 is preferably onthe longitudinal axis of the extruder. The inner width is the width ofthe open end of the dovetail groove 11, and the outer width is the widthof the bottom surface of the dovetail groove 15.

Preferably each of the dovetail grooves 11 have a substantiallytriangular cross-sectional shape; for example, the width of each thedovetail grooves 11 can continuously increase as the dovetail grooves 11extend outward relative to the center of the opening 15. In anembodiment where the opening 15 is circular, the open ends of thedovetail grooves 15 can be positioned along a first circumference, andthe bottom surfaces of the dovetail grooves 15 can be positioned along asecond circumference concentric with the first circumference but largerthan the first circumference.

In an embodiment, the dovetail grooves 11 can be formed by projections12 that extend inward from the inner periphery 16 of the opening 15. Theinner widths of the projections 12 can be positioned on the same firstcircumference as the inner widths of the dovetail grooves 11, the outerwidths of the projections 12 can be positioned on the same secondcircumference as the outer widths of the dovetail grooves 11, and eachof the outer widths of the projections 12 can be shorter then thecorresponding inner width of the projection 12. The figure shows ten ofthe dovetail grooves 11 and ten of the projections 12, but any numbercan be used, and the extrusion die 10 is not limited to a specificnumber of the dovetail grooves 11 and the projections 12.

Without being bound by theory, the inventors believe that known dieswith little straight grooves all around give a product with alternatingsmooth and blistered surfaces, the smooth surfaces corresponding to theexternal part of the grooves. The inventors believe that the flow insidethe grooves is slightly reduced, resulting in lower pressure, whichprevents the development of steam bubbles as extensively as in the diecore (less “flashing”). Replacing straight and narrow grooves with largedovetail grooves provides a product with a better cosmetic impression,due to the smooth surface being larger.

Additionally or alternatively to using an extrusion die comprisingdovetail grooves, a bicarbonate such as sodium bicarbonate can beincluded in the dry mix. For example, the dry mix can comprise 0.2 to1.5 wt % sodium bicarbonate, for example 0.5 to 1.5 wt % sodiumbicarbonate. Without being bound by theory, the inventors believe thatthe carbon dioxide released from the bicarbonate submitted to heatand/or acid promote nucleation (more nucleation sites) and helps todecrease the size of the foam cells that form in the material duringextrusion.

In a second embodiment, a low density (a density of about 1.0 Kg/L orless, such as about 1.0, or even about 0.9 Kg/L or less, such as about0.9 Kg/L) and a smooth exterior surface of the edible pet chew can beachieved by incorporating air into the dough during extrusion to aeratethe dough. In this second embodiment, the expansion can be primarily ina radial direction, although the use of a bicarbonate such as sodiumbicarbonate can result in combined axial and radial expansion in thisembodiment.

In this embodiment, the extruder can comprise a barrel comprising a ventthat is open to the atmosphere and comprising a vent-stuffer, and thedough in the venting barrel must be viscous enough to entrap air. Areverse element can be positioned after the venting barrel to maintainthe dough for an extended period of time in the venting barrel. Thereverse element can be a reverse screw element or any element thatgenerates backpressure in the extruder. The extended period of timespent by the dough in the venting barrel in the presence of the mixingelements therein can ensure an efficient mixing and/or whipping of thedough. The vent in the venting barrel that is open to the atmosphere canallow air to penetrate into the extruder and push the dough, potentiallycoming through the vent, back into the extruder. However, in a preferredembodiment, forced gas injection is not used.

This “whipping” process promotes nucleation such that a very foamy andlight dough is obtained. The phenomenon is visible right after the frontplate, on the opposite of the previous alternatives where the bubblesmainly grow at the die exhaust. Because of the very tiny bubble size,product surface is smooth and product shape well defined.

Addition of a bicarbonate such as sodium bicarbonate to the dry mix canincrease the nucleation even further. The density may thus be evenlighter (about 0.7 Kg/L or less, such as about 0.7 Kg/L) and, in someconditions, the bubbles may be hardly visible even though the density isreduced by more than 50% relative to commercial edible pet chews.

In the first and second embodiments, as well as any other embodimentsused to make the edible pet chew, the edible chew can be used in a pettreat in which the edible chew surrounds one or more fillings. Each ofthe one or more fillings may contain teeth cleaning compounds, such asTetrasodium Pyrophosphate (TSPP) and/or or breath-freshening compounds.In an embodiment, at least one of the edible pet chew or the fillingcomprises a probiotic micro-organism. The one or more fillings canextend parallel to the radial ridges of the edible pet chew.

The pet treat can be made by co-extruding the edible pet chew and theone or more fillings. For example, as generally shown in FIG. 9B, one ormore filling ports (internal inserts) can be inserted in the chewinserts (external insert); the distance between the internal inserts andthe distance between the internal inserts and the external insert arelarge enough to allow the chew dough to circulate without any preferredflow; the section of the internal inserts should be large enough toavoid too high pressure.

EXAMPLES

By way of example and not limitation, the following examples areillustrative of embodiments of the present disclosure.

Example 1

Ingredients for a 500 Kg batch of Dry Mix were weighed out according tothe percentages shown in Table 1 into a batch mixer and blended for fiveminutes. Although pre-gelled corn flour was used, additionally oralternatively any pre-gelled cereal flour can be used.

The Dry Mix was metered into an Evolum EV53 (Clextral) twin screwextruder along with the glycerin/phosphoric acid mixture and water inthe proportions shown in Table 1 and equaling 115 Kg/hour, where theywere mixed under pressure (64 bars) and achieved a temperature of 117°C. to form a plastic dough. Phosphoric acid is not required but wasincluded for additional preservative effect.

TABLE 1 Amount Ingredients (%) DRY MIX Pregelled Corn Flour 83.58 WheatFlour 6.0 Brewer's Dried Yeast 3.0 Calcium Hydrogen Phosphate 3.0Distilled Monoglyceride 1.5 Vitamin Premix 1.5 Potassium Sorbate 0.6Titanium Dioxide 0.4 Calcium Propionate 0.4 BHT Powder 0.02 TOTAL 100EXTRUSION Dry Mix 73.9 Glycerin/Phosphoric Acid (16:1) 16.3 Water 9.8TOTAL 100

The extruder was equipped with 10 barrel sections and had an L/D ratioof 40. To achieve moderate shearing, one reversing screw element wasinserted at the end of the fourth barrel, and two such elements wereinserted at the end of the fifth barrel. The screws turned at 140 rpmand attained a specific mechanical energy (SME) of 430 KJ/Kg drymaterials input. Barrels 7-10 were heated. The plastic dough was thenextruded through a die system with opening shown in FIG. 6 and cut into120 mm long dense pieces having a density of 0.9 Kg/L (FIG. 1). The diewith dovetail design (FIG. 6) was found to avoid a blistered, roughouter surface and produce an acceptably smooth outer surface (FIGS. 7Aand 7B), and the edible chew had an expanded cellular internal structure(FIG. 11). Moreover, a single tubular insert was inserted within the dieopening to form a hollow part in the product piece (FIG. 1).

Although the single insert was cylindrical, the insert can be any shape,such as triangular, rectangular, polygonal, star-shaped, or the like, toform a corresponding cross-sectional shape of the hollow part of thechew; FIG. 8 depicts an embodiment of the edible pet chew made using astar-shaped insert. Furthermore, although the die was cylindrical, thedie can be any symmetrical or non-symmetrical shape to form acorresponding cross-sectional shape of the body of the chew, as shown inFIGS. 10A and 10B.

Example 2

Example 1 was repeated with the following exceptions. 0.5% sodiumbicarbonate was added to the dry mix shown in Table 1 and the pre-gelledcorn flour was reduced accordingly to 83.08%. The maximum pressure andSME were 67 bars and 447 KJ/Kg respectively. The plastic dough was thenextruded through a die system with opening shown in FIG. 6 and cut into120 mm long pieces having a density of 0.74 Kg/L and with an expandedcellular internal structure (FIG. 2). The die with dovetail design (FIG.6) was found to avoid a blistered, rough outer surface and produce anacceptably smooth outer surface. Moreover, a single tubular insert wasinserted within the die opening to form a hollow part in the productpiece (FIG. 2).

Example 3

Example 2 was repeated with the following exceptions. 1% sodiumbicarbonate was added to the dry mix shown in Table 1 and the pre-gelledcorn flour was reduced accordingly to 82.58%. The maximum pressure andSME were 67 bars and 452 KJ/Kg respectively. The plastic dough was thenextruded through a die system with opening shown in FIG. 6 and cut into120 mm long pieces having a density of 0.68 Kg/L and with an expandedcellular internal structure (FIG. 3). The die with dovetail design (FIG.6) was found to avoid a blistered, rough outer surface and produce anacceptably smooth outer surface. Moreover, a single tubular insert wasinserted within the die opening to form a hollow part in the productpiece (FIG. 3).

Example 4

Example 3 was repeated with the following exceptions. 0.25% sodiumbicarbonate was added to the Dry Mix as shown in Table 2. The Dry Mixwas metered at 230 Kg/hr into an Evolum EV 53 (Clextral) twin screwextruder along with glycerin and water in proportions shown in Table 2.The screw speed, maximum pressure, temperature, and SME were 350 rpm, 90bars, 113° C., and 530 KJ/Kg respectively. The plastic dough was thenextruded through a die system with opening shown in FIG. 6 and cut into130 mm long pieces having a density of 0.76 Kg/L and with an expandedcellular internal structure (FIG. 3). The die with dovetail design (FIG.6) was found to avoid a blistered, rough outer surface and produce anacceptably smooth outer surface. Moreover, a single tubular insert wasinserted within the die opening to form a hollow part in the productpiece (FIG. 3).

TABLE 2 Amount Ingredients (%) DRY MIX Pregelled Corn Flour 79.80 WheatFlour 6.39 Calcium Hydrogen Phosphate 4.86 Brewer's Dried Yeast 3.00Distilled Monoglyceride 1.50 Chicken by product 1.45 Vitamin Premix 0.89Roasted malt flour 0.80 Potassium Sorbate 0.60 Calcium Propionate 0.41Sodium bicarbonate 0.25 Silicium dioxide 0.03 BHT Powder 0.02 TOTAL 100EXTRUSION Dry Mix 75.7 Glycerin 14.0 Water 10.3 TOTAL 100

Example 5

Example 1 was repeated with the following exceptions. The screw profilewas modified for high shear. To achieve this high shear, an additionalreversing screw element was inserted at the head of the seventh barrel.To allow air incorporation, a vent-stuffer was inserted on the sixthbarrel, and two mixing elements were inserted in the middle of the sixthbarrel below the vent-stuffer. The maximum pressure and SME were 66 barsand 475 KJ/Kg respectively. The plastic dough was then extruded througha die system with opening shown in FIG. 6 and cut into 120 mm longpieces having a density of 0.67 Kg/L and with an expanded cellularinternal structure (FIG. 4). The die with dovetail design (FIG. 6) wasfound to avoid a blistered, rough outer surface and produce anacceptably smooth outer surface. Moreover, a single tubular insert wasinserted within the die opening to form a hollow part in the productpiece (FIG. 4).

Example 6

Example 4 was repeated with the following exceptions. 0.5% sodiumbicarbonate was added to the dry mix shown in Table 1 and the pre-gelledcorn flour was reduced accordingly to 83.08%. The maximum pressure andSME were 62 bars and 450 KJ/Kg respectively. The plastic dough was thenextruded through a die system with opening shown in FIG. 6 and cut into120 mm long pieces having a density of 0.51 Kg/L and with an expandedfine cellular internal structure (FIG. 5). The die with dovetail design(FIG. 6) was found to avoid a blistered, rough outer surface and producean acceptably smooth outer surface. Moreover, a single tubular insertwas inserted within the die opening to form a hollow part in the productpiece (FIG. 5).

Example 7

Ingredients for a 909 Kg batch of Dry Mix were weighed out according tothe percentages shown in Table 3 into a batch mixer and blended. The DryMix was metered into a Single Screw Extruder equipped with apre-conditioner along with the glycerin, water and phosphoric acid inthe proportions shown in Table 3, where they were mixed under pressure(60 bars) and achieved a temperature of 110° C. to form a plastic dough.

TABLE 3 Amount Ingredients (%) DRY MIX Pregelled Rice Flour 73.86 WheatFlour 17.10 Monocalcium-Dicalcium 1.00 Phophaste Distilled Monoglyceride1.80 Chicken by product meal 2.50 Sorbic acid 0.50 Roasted malt flour2.58 Calcium Propionate 0.33 Sodium bicarbonate 0.30 BHA/BHT Powder 0.03TOTAL 100 EXTRUSION Dry Mix 76.38 Glycerin 11.46 Water 11.22 Phosphoricacid 0.94 TOTAL 100

The extruder was equipped to achieve shearing in the last section of thescrew. The screw turned at 50-100 rpm. Temperature of the barrel of thescrew was controlled. The plastic dough was then extruded through a diesystem with opening shown in FIG. 6 and cut into 127 mm long pieceshaving a porous structure (FIG. 1) and density 0.9 Kg/L. The die withdovetail design (FIG. 6) was found to avoid a blistered, rough outersurface and produce an acceptably smooth outer surface (FIGS. 7A and7B), and the edible chew had an expanded cellular internal structure(FIG. 11).

Example 8

For variation, multiple tubular inserts (FIG. 9B) were inserted withinthe die opening to form several hollow parts in the product piece (FIGS.9C and 9D). The hollow sections were filled with a functional dough orpaste using a system having a co-filling port (FIG. 9A).

Example 9

A dental efficacy test was carried out with products made according toExample 4 with star-shaped hollow pieces of weight 26 g (Experimental)and compared with a commercial dental product (Commercial) with similaringredients that was not expanded (puffed). The following test protocolwas employed:

16 medium dogs selected (good health and have none of the consideredteeth missing)

Testing—crossover design: each dog was submitted to control diet (wetfood) and experimental diet (wet food+1 dental stick)

1 stick of 26 g represented 10% of the daily energy intake for a mediumdog

Preliminary phase: 1 week adaptation to allow dogs to get accustomed todental product

Followed by teeth cleaning and polishing/weight control

1st phase: for 28 days, group 1 (8 dogs) received control diet and group2 (8 dogs) received experimental diet

Gingival index, plaque & tartar development scoring was done onconsidered teeth and followed up with teeth cleaning and polishing

2nd phase: for the next 28 days, group 1 (8 dogs) received experimentaldiet and group 2 (8 dogs) received control diet

Gingival index, plaque & tartar development scoring on consideredteeth/teeth cleaning and polishing

This procedure was repeated with 26 g pieces of the commercial dentalproduct.

Statistical analyses were carried out on both sets of data, and theresults are shown in Table 4.

TABLE 4 Plaque Score Tartar Score % of % of Gingival dogs Highest dogsScore with a Average tartar with a Average Average positive plaque buildup positive tartar gingivitis reduction buildup reduction reductionbuild up Calorie score of plaque reduction score of tartar reductionDensity reduction buildup score recorded build up score Kcal/cm³Commercial NS 62.50% 10.90% 57.60% 86.70% 32.70% 3.6 ProductExperimental 19.00% 81.20% 18.40% 70.00% 100.00% 52.40% 2.1 Product

From these results, it is clearly seen that the puffed (expanded)product had better dental cleaning scores than a current unexpandedsimilarly formulated commercial dental product on an equal caloriebasis.

It should be understood that various changes and modifications to thepresently preferred embodiments described herein will be apparent tothose skilled in the art. Such changes and modifications can be madewithout departing from the spirit and scope of the present subjectmatter and without diminishing its intended advantages. It is thereforeintended that such changes and modifications be covered by the appendedclaims.

The invention is claimed as follows:
 1. An edible pet chew comprising anexpanded pre-gelatinized cereal flour matrix and having a substantiallysmooth exterior surface and a density not greater than about 1.0 Kg/L.2. The edible pet chew of claim 1 wherein the chew has a form of singleunitary piece.
 3. The edible pet chew of claim 1 wherein the chew doesnot contain a supercritical fluid.
 4. The edible pet chew of claim 1wherein the chew has a caloric density of 1.5-2.7 Kcal/cm³.
 5. Theedible pet chew of claim 1 wherein the density is at most about 0.9Kg/L.
 6. The edible pet chew of claim 1 wherein the chew comprises abody having a substantially cylindrical shape and comprises radialridges extending from the body parallel to each other along at least aportion of the length of the body.
 7. A method of making an edible petchew, the method comprising the steps of: preparing a dry mix comprisinga pre-gelatinized cereal flour; metering the dry mix into an extrudercomprising an extrusion die; adding a hydrogen bond-forming component tothe dry mix to form a dough; promoting nucleation of the dough bysubjecting the dough to a combination of shear and a temperature in asection of the extruder adjacent to the extrusion die to form a heatedand sheared dough, the temperature in the section adjacent to theextrusion die is higher than a temperature of at least one previoussection of the extruder; and directing the heated and sheared doughthrough an opening of the extrusion die comprising grooves, each of thegrooves has an open end and a bottom surface opposite to the open end,and the width of the bottom surface is greater than the width of theopen end.
 8. The method of claim 7 wherein the grooves have asubstantially triangular cross-section.
 9. The method of claim 7 whereinthe grooves have a width that continuously decreases as the groovesextend toward the center of the opening.
 10. The method of claim 7wherein the grooves are evenly spaced along an inner periphery of theopening of the extrusion die.
 11. The method of claim 7 wherein thetemperature in the section of the extruder adjacent to the extrusion dieis at least 120° C.
 12. The method of claim 7 wherein the hydrogenbond-forming component comprises a polyhydric solvent.
 13. A method ofmaking an edible pet chew, the method comprising the steps of: forming adry mix comprising a pre-gelatinized cereal flour and a bicarbonate;metering the dry mix into an extruder comprising an extrusion die;adding a hydrogen bond-forming component to the dry mix to form a dough;and promoting nucleation of the dough by subjecting the dough to acombination of shear and a temperature in a section of the extruderadjacent to the extrusion die, the temperature in the section adjacentto the extrusion die is higher than a temperature of at least oneprevious section of the extruder to form a heated and sheared dough. 14.The method of claim 13 wherein the bicarbonate is sodium bicarbonate.15. The method of claim 14 wherein the dry mix comprises 0.2 to 1.5 wt %of the sodium bicarbonate.
 16. A method of making an edible pet chew,the method comprising the steps of: forming a dry mix comprising apre-gelatinized cereal flour; metering the dry mix into an extrudercomprising an extrusion die and a barrel comprising a vent and avent-stuffer; adding a hydrogen bond-forming component to the dry mix toform a dough; using a reverse element of the extruder to extend a timespent by the dough in the barrel comprising the vent and thevent-stuffer; using mixing elements in the barrel comprising the ventand the vent-stuffer to whip the dough and promote nucleation of thedough; and promoting further nucleation of the dough by subjecting thedough to a combination of shear and temperature in a section of theextruder adjacent to the extrusion die to form a heated and sheareddough, the temperature in the section adjacent to the extrusion die ishigher than a temperature of at least one previous section of theextruder.
 17. The method of claim 16 comprising adding a bicarbonate tothe dry mix.
 18. The method of claim 16 comprising aerating the dough inthe barrel comprising the vent and the vent-stuffer.
 19. The method ofclaim 16 wherein the vent is configured to provide ambient pressure. 20.An edible pet chew made by a process selected from the group consistingof the method of claim 7, the method of claim 13, and the method ofclaim
 16. 21. A pet treat comprising: an edible pet chew comprising anexpanded pre-gelatinized cereal flour matrix and having a substantiallysmooth exterior surface and a density not greater than about 1.0 Kg/L;and at least one filling comprising radial sides surrounded by theedible pet chew.
 22. A method of cleaning teeth of a pet, the methodcomprising administering to the pet an edible pet chew comprising anexpanded pre-gelatinized cereal flour matrix and having a substantiallysmooth exterior surface and a density not greater than about 1.0 Kg/L.